1
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Howe CJ, Barbrook AC. Dinoflagellate chloroplasts as a model for extreme genome reduction and fragmentation in organelles - The COCOA principle for gene retention. Protist 2024; 175:126048. [PMID: 38981407 DOI: 10.1016/j.protis.2024.126048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 07/11/2024]
Abstract
The genomes of peridinin-containing dinoflagellate chloroplasts have a very unusual organisation. These genomes are highly fragmented and greatly reduced, with most of the usual complement of chloroplast genes relocated to the nucleus. Dinoflagellate chloroplasts highlight evolutionary changes that are found to varying extents in a number of other organelle genomes. These include the chloroplast genome of the green alga Boodlea and other Cladophorales, and the mitochondrial genomes of blood-sucking and chewing lice, the parasitic plant Rhopalocnemis phalloides, the red alga Rhodosorus marinus and other members of the Stylonematophyceae, diplonemid flagellates, and some Cnidaria. Consideration of the coding content of the remnant chloroplast genomes indicates that organelles may preferentially retain genes for proteins important in initiating assembly of complexes, and the same is largely true for mitochondria. We propose a new principle, of CO-location for COntrol of Assembly (COCOA), indicating the importance of retaining these genes in the organelle. This adds to, but does not invalidate, the existing hypotheses of the multisubunit completion principle, CO-location for Redox Regulation (CORR) and Control by Epistasy of Synthesis (CES).
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Affiliation(s)
- Christopher J Howe
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK; Stellenbosch Institute for Advanced Study, (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch 7600, South Africa.
| | - Adrian C Barbrook
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK.
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2
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Fang J, Xu X, Chen Q, Lin A, Lin S, Lei W, Zhong C, Huang Y, He Y. The complete mitochondrial genome of Isochrysis galbana harbors a unique repeat structure and a specific trans-spliced cox1 gene. Front Microbiol 2022; 13:966219. [PMID: 36238593 PMCID: PMC9551565 DOI: 10.3389/fmicb.2022.966219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/25/2022] [Indexed: 11/13/2022] Open
Abstract
The haptophyte Isochrysis galbana is considered as a promising source for food supplements due to its rich fucoxanthin and polyunsaturated fatty acids content. Here, the I. galbana mitochondrial genome (mitogenome) was sequenced using a combination of Illumina and PacBio sequencing platforms. This 39,258 bp circular mitogenome has a total of 46 genes, including 20 protein-coding genes, 24 tRNA genes and two rRNA genes. A large block of repeats (~12.7 kb) was segregated in one region of the mitogenome, accounting for almost one third of the total size. A trans-spliced gene cox1 was first identified in I. galbana mitogenome and was verified by RNA-seq and DNA-seq data. The massive expansion of tandem repeat size and cis- to trans-splicing shift could be explained by the high mitogenome rearrangement rates in haptophytes. Strict SNP calling based on deep transcriptome sequencing data suggested the lack of RNA editing in both organelles in this species, consistent with previous studies in other algal lineages. To gain insight into haptophyte mitogenome evolution, a comparative analysis of mitogenomes within haptophytes and among eight main algal lineages was performed. A core gene set of 15 energy and metabolism genes is present in haptophyte mitogenomes, consisting of 1 cob, 3 cox, 7 nad, 2 atp and 2 ribosomal genes. Gene content and order was poorly conserved in this lineage. Haptophyte mitogenomes have lost many functional genes found in many other eukaryotes including rps/rpl, sdh, tat, secY genes, which make it contain the smallest gene set among all algal taxa. All these implied the rapid-evolving and more recently evolved mitogenomes of haptophytes compared to other algal lineages. The phylogenetic tree constructed by cox1 genes of 204 algal mitogenomes yielded well-resolved internal relationships, providing new evidence for red-lineages that contained plastids of red algal secondary endosymbiotic origin. This newly assembled mitogenome will add to our knowledge of general trends in algal mitogenome evolution within haptophytes and among different algal taxa.
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Affiliation(s)
- Jingping Fang
- College of Life Science, Fujian Normal University, Fuzhou, China
- Center of Engineering Technology Research for Microalgae Germplasm Improvement of Fujian, Southern Institute of Oceanography, Fujian Normal University, Fuzhou, China
- *Correspondence: Jingping Fang,
| | - Xiuming Xu
- College of Life Science, Fujian Normal University, Fuzhou, China
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, China
- Xiuming Xu,
| | - Qinchang Chen
- College of Life Science, Fujian Normal University, Fuzhou, China
- Center of Engineering Technology Research for Microalgae Germplasm Improvement of Fujian, Southern Institute of Oceanography, Fujian Normal University, Fuzhou, China
| | - Aiting Lin
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shaoqing Lin
- College of Life Science, Fujian Normal University, Fuzhou, China
| | - Wen Lei
- College of Life Science, Fujian Normal University, Fuzhou, China
| | - Cairong Zhong
- College of Life Science, Fujian Normal University, Fuzhou, China
- Center of Engineering Technology Research for Microalgae Germplasm Improvement of Fujian, Southern Institute of Oceanography, Fujian Normal University, Fuzhou, China
| | - Yongji Huang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Geography and Oceanography, Minjiang University, Fuzhou, China
| | - Yongjin He
- College of Life Science, Fujian Normal University, Fuzhou, China
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3
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Faktorová D, Kaur B, Valach M, Graf L, Benz C, Burger G, Lukeš J. Targeted integration by homologous recombination enables in situ tagging and replacement of genes in the marine microeukaryote Diplonema papillatum. Environ Microbiol 2020; 22:3660-3670. [PMID: 32548939 DOI: 10.1111/1462-2920.15130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/07/2020] [Accepted: 06/13/2020] [Indexed: 12/17/2022]
Abstract
Diplonemids are a group of highly diverse and abundant marine microeukaryotes that belong to the phylum Euglenozoa and form a sister clade to the well-studied, mostly parasitic kinetoplastids. Very little is known about the biology of diplonemids, as few species have been formally described and just one, Diplonema papillatum, has been studied to a decent extent at the molecular level. Following up on our previous results showing stable but random integration of delivered extraneous DNA, we demonstrate here homologous recombination in D. papillatum. Targeting various constructs to the intended position in the nuclear genome was successful when 5' and 3' homologous regions longer than 1 kbp were used, achieving N-terminal tagging with mCherry and gene replacement of α- and β-tubulins. For more convenient genetic manipulation, we designed a modular plasmid, pDP002, which bears a protein-A tag and used it to generate and express a C-terminally tagged mitoribosomal protein. Lastly, we developed an improved transformation protocol for broader applicability across laboratories. Our robust methodology allows the replacement, integration as well as endogenous tagging of D. papillatum genes, thus opening the door to functional studies in this species and establishing a basic toolkit for reverse genetics of diplonemids in general.
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Affiliation(s)
- Drahomíra Faktorová
- Czech Academy of Sciences, Institute of Parasitology, Biology Centre, Czech Republic.,Faculty of Sciences, University of South Bohemia, Cˇeské Budějovice (Budweis), Czech Republic
| | - Binnypreet Kaur
- Czech Academy of Sciences, Institute of Parasitology, Biology Centre, Czech Republic.,Faculty of Sciences, University of South Bohemia, Cˇeské Budějovice (Budweis), Czech Republic
| | - Matus Valach
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Lena Graf
- Faculty of Sciences, University of South Bohemia, Cˇeské Budějovice (Budweis), Czech Republic.,Present address: Johannes Kepler University, Linz, Austria
| | - Corinna Benz
- Czech Academy of Sciences, Institute of Parasitology, Biology Centre, Czech Republic
| | - Gertraud Burger
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Julius Lukeš
- Czech Academy of Sciences, Institute of Parasitology, Biology Centre, Czech Republic.,Faculty of Sciences, University of South Bohemia, Cˇeské Budějovice (Budweis), Czech Republic
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4
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Kaur B, Záhonová K, Valach M, Faktorová D, Prokopchuk G, Burger G, Lukeš J. Gene fragmentation and RNA editing without borders: eccentric mitochondrial genomes of diplonemids. Nucleic Acids Res 2020; 48:2694-2708. [PMID: 31919519 PMCID: PMC7049700 DOI: 10.1093/nar/gkz1215] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/14/2019] [Accepted: 01/08/2020] [Indexed: 11/20/2022] Open
Abstract
Diplonemids are highly abundant heterotrophic marine protists. Previous studies showed that their strikingly bloated mitochondrial genome is unique because of systematic gene fragmentation and manifold RNA editing. Here we report a comparative study of mitochondrial genome architecture, gene structure and RNA editing of six recently isolated, phylogenetically diverse diplonemid species. Mitochondrial gene fragmentation and modes of RNA editing, which include cytidine-to-uridine (C-to-U) and adenosine-to-inosine (A-to-I) substitutions and 3' uridine additions (U-appendage), are conserved across diplonemids. Yet as we show here, all these features have been pushed to their extremes in the Hemistasiidae lineage. For example, Namystynia karyoxenos has its genes fragmented into more than twice as many modules than other diplonemids, with modules as short as four nucleotides. Furthermore, we detected in this group multiple A-appendage and guanosine-to-adenosine (G-to-A) substitution editing events not observed before in diplonemids and found very rarely elsewhere. With >1,000 sites, C-to-U and A-to-I editing in Namystynia is nearly 10 times more frequent than in other diplonemids. The editing density of 12% in coding regions makes Namystynia's the most extensively edited transcriptome described so far. Diplonemid mitochondrial genome architecture, gene structure and post-transcriptional processes display such high complexity that they challenge all other currently known systems.
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Affiliation(s)
- Binnypreet Kaur
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Kristína Záhonová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic
- Faculty of Science, Charles University, BIOCEV, 25250 Vestec, Czech Republic
| | - Matus Valach
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, H3T 1J4 Montreal, Canada
| | - Drahomíra Faktorová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Galina Prokopchuk
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic
| | - Gertraud Burger
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, H3T 1J4 Montreal, Canada
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
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5
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Butenko A, Opperdoes FR, Flegontova O, Horák A, Hampl V, Keeling P, Gawryluk RMR, Tikhonenkov D, Flegontov P, Lukeš J. Evolution of metabolic capabilities and molecular features of diplonemids, kinetoplastids, and euglenids. BMC Biol 2020; 18:23. [PMID: 32122335 PMCID: PMC7052976 DOI: 10.1186/s12915-020-0754-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/17/2020] [Indexed: 12/24/2022] Open
Abstract
Background The Euglenozoa are a protist group with an especially rich history of evolutionary diversity. They include diplonemids, representing arguably the most species-rich clade of marine planktonic eukaryotes; trypanosomatids, which are notorious parasites of medical and veterinary importance; and free-living euglenids. These different lifestyles, and particularly the transition from free-living to parasitic, likely require different metabolic capabilities. We carried out a comparative genomic analysis across euglenozoan diversity to see how changing repertoires of enzymes and structural features correspond to major changes in lifestyles. Results We find a gradual loss of genes encoding enzymes in the evolution of kinetoplastids, rather than a sudden decrease in metabolic capabilities corresponding to the origin of parasitism, while diplonemids and euglenids maintain more metabolic versatility. Distinctive characteristics of molecular machines such as kinetochores and the pre-replication complex that were previously considered specific to parasitic kinetoplastids were also identified in their free-living relatives. Therefore, we argue that they represent an ancestral rather than a derived state, as thought until the present. We also found evidence of ancient redundancy in systems such as NADPH-dependent thiol-redox. Only the genus Euglena possesses the combination of trypanothione-, glutathione-, and thioredoxin-based systems supposedly present in the euglenozoan common ancestor, while other representatives of the phylum have lost one or two of these systems. Lastly, we identified convergent losses of specific metabolic capabilities between free-living kinetoplastids and ciliates. Although this observation requires further examination, it suggests that certain eukaryotic lineages are predisposed to such convergent losses of key enzymes or whole pathways. Conclusions The loss of metabolic capabilities might not be associated with the switch to parasitic lifestyle in kinetoplastids, and the presence of a highly divergent (or unconventional) kinetochore machinery might not be restricted to this protist group. The data derived from the transcriptomes of free-living early branching prokinetoplastids suggests that the pre-replication complex of Trypanosomatidae is a highly divergent version of the conventional machinery. Our findings shed light on trends in the evolution of metabolism in protists in general and open multiple avenues for future research.
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Affiliation(s)
- Anzhelika Butenko
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Fred R Opperdoes
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Olga Flegontova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Aleš Horák
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Vladimír Hampl
- Faculty of Science, Charles University, Biocev, Vestec, Czech Republic
| | - Patrick Keeling
- Department of Botany, University of British Columbia, Vancouver, Canada
| | | | - Denis Tikhonenkov
- Department of Botany, University of British Columbia, Vancouver, Canada.,Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Russia
| | - Pavel Flegontov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic. .,Faculty of Science, University of Ostrava, Ostrava, Czech Republic. .,Present address: Department of Genetics, Harvard Medical School, Boston, USA.
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic. .,Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
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6
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Gerasimov ES, Gasparyan AA, Kaurov I, Tichý B, Logacheva MD, Kolesnikov AA, Lukeš J, Yurchenko V, Zimmer SL, Flegontov P. Trypanosomatid mitochondrial RNA editing: dramatically complex transcript repertoires revealed with a dedicated mapping tool. Nucleic Acids Res 2019; 46:765-781. [PMID: 29220521 PMCID: PMC5778460 DOI: 10.1093/nar/gkx1202] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/20/2017] [Indexed: 12/22/2022] Open
Abstract
RNA editing by targeted insertion and deletion of uridine is crucial to generate translatable mRNAs from the cryptogenes of the mitochondrial genome of kinetoplastids. This type of editing consists of a stepwise cascade of reactions generally proceeding from 3′ to 5′ on a transcript, resulting in a population of partially edited as well as pre-edited and completely edited molecules for each mitochondrial cryptogene of these protozoans. Often, the number of uridines inserted and deleted exceed the number of nucleotides that are genome-encoded. Thus, analysis of kinetoplastid mitochondrial transcriptomes has proven frustratingly complex. Here we present our analysis of Leptomonas pyrrhocoris mitochondrial cDNA deep sequencing reads using T-Aligner, our new tool which allows comprehensive characterization of RNA editing, not relying on targeted transcript amplification and on prior knowledge of final edited products. T-Aligner implements a pipeline of read mapping, visualization of all editing states and their coverage, and assembly of canonical and alternative translatable mRNAs. We also assess T-Aligner functionality on a more challenging deep sequencing read input from Trypanosoma cruzi. The analysis reveals that transcripts of cryptogenes of both species undergo very complex editing that includes the formation of alternative open reading frames and whole categories of truncated editing products.
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Affiliation(s)
- Evgeny S Gerasimov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow 127051, Russia
| | - Anna A Gasparyan
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Iosif Kaurov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice 370 05, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice 370 05, Czech Republic
| | - Boris Tichý
- Central European Institute of Technology, Masaryk University, Brno 625 00, Czech Republic
| | - Maria D Logacheva
- Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Russia Extreme Biology Laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, 420008, Russia.,Skolkovo Institute of Science and Technology, Moscow, 14326, Russia
| | | | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice 370 05, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice 370 05, Czech Republic
| | - Vyacheslav Yurchenko
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice 370 05, Czech Republic.,Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava 710 00, Czech Republic.,Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava 710 00, Czech Republic
| | - Sara L Zimmer
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812-3031, USA
| | - Pavel Flegontov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice 370 05, Czech Republic.,Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava 710 00, Czech Republic
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7
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Morphological, Ultrastructural, Motility and Evolutionary Characterization of Two New Hemistasiidae Species. Protist 2019; 170:259-282. [PMID: 31154071 DOI: 10.1016/j.protis.2019.04.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/26/2019] [Accepted: 04/04/2019] [Indexed: 11/21/2022]
Abstract
Until now, Hemistasia phaeocysticola was the only representative of the monogeneric family Hemistasiidae available in culture. Here we describe two new axenized hemistasiids isolated from Tokyo Bay, Japan. Like in other diplonemids, cellular organization of these heterotrophic protists is characterized by a distinct apical papilla, a tubular cytopharynx contiguous with a deep flagellar pocket, and a highly branched mitochondrion with lamellar cristae. Both hemistasiids also bear a prominent digestive vacuole, peripheral lacunae, and paraflagellar rods, are highly motile and exhibit diverse morphologies in culture. We argue that significant differences in molecular phylogenetics and ultrastructure between these new species and H. phaeocysticola are on the generic level. Therefore, we have established two new genera within Hemistasiidae - Artemidia gen. n. and Namystynia gen. n. to accommodate Artemidia motanka, sp. n. and Namystynia karyoxenos, sp. n., respectively. A. motanka permanently carries tubular extrusomes, while in N. karyoxenos, they are present only in starving cells. An additional remarkable feature of the latter species is the presence, in both the cytoplasm and the nucleus, of the endosymbiotic rickettsiid Candidatus Sneabacter namystus.
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8
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Burger G, Valach M. Perfection of eccentricity: Mitochondrial genomes of diplonemids. IUBMB Life 2018; 70:1197-1206. [PMID: 30304578 DOI: 10.1002/iub.1927] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 01/14/2023]
Abstract
Mitochondria are the sandbox of evolution as exemplified most particularly by the diplonemids, a group of marine microeukaryotes. These protists are uniquely characterized by their highly multipartite mitochondrial genome and systematically fragmented genes whose pieces are spread out over several dozens of chromosomes. The type species Diplonema papillatum was the first member of this group in which the expression of fragmented mitochondrial genes was investigated experimentally. We now know that gene expression involves separate transcription of gene pieces (modules), RNA editing of module transcripts, and module joining to mature mRNAs and rRNAs. The mechanism of cognate module recognition and ligation is distinct from known intron splicing and remains to be uncovered. Here, we review the current status of research on mitochondrial genome architecture, as well as gene complement, structure, and expression modes in diplonemids. Further, we discuss the potential molecular mechanisms of posttranscriptional processing, and finally reflect on the evolutionary trajectories and trends of mtDNA evolution as seen in this protist group. © 2018 IUBMB Life, 70(12):1197-1206, 2018.
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Affiliation(s)
- Gertraud Burger
- Département de Biochimie, Robert Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montréal, Québec, Canada
| | - Matus Valach
- Département de Biochimie, Robert Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montréal, Québec, Canada
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9
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Lukeš J, Wheeler R, Jirsová D, David V, Archibald JM. Massive mitochondrial DNA content in diplonemid and kinetoplastid protists. IUBMB Life 2018; 70:1267-1274. [PMID: 30291814 PMCID: PMC6334171 DOI: 10.1002/iub.1894] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/11/2018] [Accepted: 06/12/2018] [Indexed: 11/25/2022]
Abstract
The mitochondrial DNA of diplonemid and kinetoplastid protists is known for its suite of bizarre features, including the presence of concatenated circular molecules, extensive trans‐splicing and various forms of RNA editing. Here we report on the existence of another remarkable characteristic: hyper‐inflated DNA content. We estimated the total amount of mitochondrial DNA in four kinetoplastid species (Trypanosoma brucei, Trypanoplasma borreli, Cryptobia helicis, and Perkinsela sp.) and the diplonemid Diplonema papillatum. Staining with 4′,6‐diamidino‐2‐phenylindole and RedDot1 followed by color deconvolution and quantification revealed massive inflation in the total amount of DNA in their organelles. This was further confirmed by electron microscopy. The most extreme case is the ∼260 Mbp of DNA in the mitochondrion of Diplonema, which greatly exceeds that in its nucleus; this is, to our knowledge, the largest amount of DNA described in any organelle. Perkinsela sp. has a total mitochondrial DNA content ~6.6× greater than its nuclear genome. This mass of DNA occupies most of the volume of the Perkinsela cell, despite the fact that it contains only six protein‐coding genes. Why so much DNA? We propose that these bloated mitochondrial DNAs accumulated by a ratchet‐like process. Despite their excessive nature, the synthesis and maintenance of these mtDNAs must incur a relatively low cost, considering that diplonemids are one of the most ubiquitous and speciose protist groups in the ocean. © 2018 The Authors. IUBMB Life published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology., 70(12):1267–1274, 2018
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Affiliation(s)
- Julius Lukeš
- Institute of ParasitologyBiology Centre, Czech Academy of SciencesČeské Budějovice (Budweis)Czech Republic
- Faculty of ScienceUniversity of South BohemiaČeské Budějovice (Budweis)Czech Republic
| | - Richard Wheeler
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
| | - Dagmar Jirsová
- Institute of ParasitologyBiology Centre, Czech Academy of SciencesČeské Budějovice (Budweis)Czech Republic
| | - Vojtěch David
- Department of Biochemistry and Molecular BiologyDalhousie UniversityHalifaxCanada
| | - John M. Archibald
- Department of Biochemistry and Molecular BiologyDalhousie UniversityHalifaxCanada
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10
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Valach M, Léveillé-Kunst A, Gray MW, Burger G. Respiratory chain Complex I of unparalleled divergence in diplonemids. J Biol Chem 2018; 293:16043-16056. [PMID: 30166340 DOI: 10.1074/jbc.ra118.005326] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial genes of Euglenozoa (Kinetoplastida, Diplonemea, and Euglenida) are notorious for being barely recognizable, raising the question of whether such divergent genes actually code for functional proteins. Here we demonstrate the translation and identify the function of five previously unassigned y genes encoded by mitochondrial DNA (mtDNA) of diplonemids. As is the rule in diplonemid mitochondria, y genes are fragmented, with gene pieces transcribed separately and then trans-spliced to form contiguous mRNAs. Further, y transcripts undergo massive RNA editing, including uridine insertions that generate up to 16-residue-long phenylalanine tracts, a feature otherwise absent from conserved mitochondrial proteins. By protein sequence analyses, MS, and enzymatic assays in Diplonema papillatum, we show that these y genes encode the subunits Nad2, -3, -4L, -6, and -9 of the respiratory chain Complex I (CI; NADH:ubiquinone oxidoreductase). The few conserved residues of these proteins are essentially those involved in proton pumping across the inner mitochondrial membrane and in coupling ubiquinone reduction to proton pumping (Nad2, -3, -4L, and -6) and in interactions with subunits containing electron-transporting Fe-S clusters (Nad9). Thus, in diplonemids, 10 CI subunits are mtDNA-encoded. Further, MS of D. papillatum CI allowed identification of 26 conventional and 15 putative diplonemid-specific nucleus-encoded components. Most conventional accessory subunits are well-conserved but unusually long, possibly compensating for the streamlined mtDNA-encoded components and for missing, otherwise widely distributed, conventional subunits. Finally, D. papillatum CI predominantly exists as a supercomplex I:III:IV that is exceptionally stable, making this protist an organism of choice for structural studies.
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Affiliation(s)
- Matus Valach
- From the Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Quebec H3T 1J4, Canada and
| | - Alexandra Léveillé-Kunst
- From the Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Quebec H3T 1J4, Canada and
| | - Michael W Gray
- the Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Gertraud Burger
- From the Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Quebec H3T 1J4, Canada and
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11
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Okamoto N, Gawryluk RMR, Del Campo J, Strassert JFH, Lukeš J, Richards TA, Worden AZ, Santoro AE, Keeling PJ. A Revised Taxonomy of Diplonemids Including the Eupelagonemidae n. fam. and a Type Species, Eupelagonema oceanica n. gen. & sp. J Eukaryot Microbiol 2018; 66:519-524. [PMID: 30080299 DOI: 10.1111/jeu.12679] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 06/16/2018] [Accepted: 07/12/2018] [Indexed: 12/20/2022]
Abstract
Recent surveys of marine microbial diversity have identified a previously unrecognized lineage of diplonemid protists as being among the most diverse heterotrophic eukaryotes in global oceans. Despite their monophyly (and assumed importance), they lack a formal taxonomic description, and are informally known as deep-sea pelagic diplonemids (DSPDs) or marine diplonemids. Recently, we documented morphology and molecular sequences from several DSPDs, one of which is particularly widespread and abundant in environmental sequence data. To simplify the communication of future work on this important group, here we formally propose to erect the family Eupelagonemidae to encompass this clade, as well as a formal genus and species description for the apparently most abundant phylotype, Eupelagonema oceanica, for which morphological information and single-cell amplified genome data are currently available.
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Affiliation(s)
- Noriko Okamoto
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Boulevard, British Columbia, Canada
| | - Ryan M R Gawryluk
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Boulevard, British Columbia, Canada
| | - Javier Del Campo
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Boulevard, British Columbia, Canada
| | - Jürgen F H Strassert
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Boulevard, British Columbia, Canada
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Faculty of Sciences, University of South Bohemia, Branišovská 31, 370 05, České Budějovice (Budweis), Czech Republic
| | - Thomas A Richards
- Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, EX4 4QD, United Kingdom
| | - Alexandra Z Worden
- Monterey Bay Aquarium Research Institute, Moss Landing, California, 95039, USA
| | - Alyson E Santoro
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, 93106, USA
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Boulevard, British Columbia, Canada
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12
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Kaur B, Valach M, Peña-Diaz P, Moreira S, Keeling PJ, Burger G, Lukeš J, Faktorová D. Transformation of Diplonema papillatum, the type species of the highly diverse and abundant marine microeukaryotes Diplonemida (Euglenozoa). Environ Microbiol 2018; 20:1030-1040. [PMID: 29318727 DOI: 10.1111/1462-2920.14041] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/13/2017] [Accepted: 12/15/2017] [Indexed: 11/30/2022]
Abstract
Diplonema papillatum is the type species of diplonemids, which are among the most abundant and diverse heterotrophic microeukaryotes in the world's oceans. Diplonemids are also known for a unique form of post-transcriptional processing in mitochondria. However, the lack of reverse genetics methodologies in these protists has hampered elucidation of their cellular and molecular biology. Here we report a protocol for D. papillatum transformation. We have identified several antibiotics to which D. papillatum is sensitive and thus are suitable selectable markers, and focus in particular on puromycin. Constructs were designed encoding antibiotic resistance markers, fluorescent tags, and additional genomic sequences from D. papillatum to facilitate vector integration into chromosomes. We established conditions for effective electroporation, and demonstrate that electroporated constructs can be stably integrated in the D. papillatum nuclear genome. In D. papillatum transformants, the heterologous puromycin resistance gene is transcribed into mRNA and translated into protein, as determined by Southern hybridization, reverse transcription, and Western blot analyses. This is the first documented case of transformation in a euglenozoan protist outside the well-studied kinetoplastids, making D. papillatum a genetically tractable organism and potentially a model system for marine microeukaryotes.
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Affiliation(s)
- Binnypreet Kaur
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Matus Valach
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Priscila Peña-Diaz
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Sandrine Moreira
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Patrick J Keeling
- Botany Department, University of British Columbia, Vancouver, Canada
| | - Gertraud Burger
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Drahomíra Faktorová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
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13
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Faktorová D, Valach M, Kaur B, Burger G, Lukeš J. Mitochondrial RNA Editing and Processing in Diplonemid Protists. RNA METABOLISM IN MITOCHONDRIA 2018. [DOI: 10.1007/978-3-319-78190-7_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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14
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Valach M, Moreira S, Hoffmann S, Stadler PF, Burger G. Keeping it complicated: Mitochondrial genome plasticity across diplonemids. Sci Rep 2017; 7:14166. [PMID: 29074957 PMCID: PMC5658414 DOI: 10.1038/s41598-017-14286-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/06/2017] [Indexed: 01/30/2023] Open
Abstract
Chromosome rearrangements are important drivers in genome and gene evolution, with implications ranging from speciation to development to disease. In the flagellate Diplonema papillatum (Euglenozoa), mitochondrial genome rearrangements have resulted in nearly hundred chromosomes and a systematic dispersal of gene fragments across the multipartite genome. Maturation into functional RNAs involves separate transcription of gene pieces, joining of precursor RNAs via trans-splicing, and RNA editing by substitution and uridine additions both reconstituting crucial coding sequence. How widespread these unusual features are across diplonemids is unclear. We have analyzed the mitochondrial genomes and transcriptomes of four species from the Diplonema/Rhynchopus clade, revealing a considerable genomic plasticity. Although gene breakpoints, and thus the total number of gene pieces (~80), are essentially conserved across this group, the number of distinct chromosomes varies by a factor of two, with certain chromosomes combining up to eight unrelated gene fragments. Several internal protein-coding gene pieces overlap substantially, resulting, for example, in a stretch of 22 identical amino acids in cytochrome c oxidase subunit 1 and NADH dehydrogenase subunit 5. Finally, the variation of post-transcriptional editing patterns across diplonemids indicates compensation of two adverse trends: rapid sequence evolution and loss of genetic information through unequal chromosome segregation.
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Affiliation(s)
- Matus Valach
- Department of biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, 2900 Edouard-Montpetit, Montreal, H3T 1J4, QC, Canada.
| | - Sandrine Moreira
- Department of biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, 2900 Edouard-Montpetit, Montreal, H3T 1J4, QC, Canada.,Department of Biochemistry and Molecular Biophysics, Columbia University, Hammer Health Science Center, 701 W 168th St, New York, NY, 10031, USA
| | - Steve Hoffmann
- Leipzig University, LIFE - Leipzig Research Center for Civilization Diseases, Haertelstrasse 16-18, Leipzig, D-04107, Germany
| | - Peter F Stadler
- Bioinformatics Group, Department Computer Science, and Interdisciplinary Center for Bioinformatics, University Leipzig, Härtelstrasse 16-18, D-04107, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Competence Center for Scalable Data Services and Solutions, and Leipzig Research Center for Civilization Diseases, University Leipzig, D-04107, Leipzig, Germany.,Max Planck Institute for Mathematics in the Sciences, Inselstrasse 22, D-04103, Leipzig, Germany.,Fraunhofer Institute for Cell Therapy and Immunology, Perlickstrasse 1, D-04103, Leipzig, Germany.,Department of Theoretical Chemistry of the University of Vienna, Währingerstrasse 17, A-1090, Vienna, Austria.,Center for RNA in Technology and Health, University of Copenhagen, Grønnegårdsvej 3, 1870, Frederiksberg C, Denmark.,Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, 87501, USA
| | - Gertraud Burger
- Department of biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, 2900 Edouard-Montpetit, Montreal, H3T 1J4, QC, Canada.
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